With the rapid development of display technologies, touch screen panels have been gradually widely applied in people's live. Currently, the touch screen panels, according to configuration, can be divided into the types of add-on touch panels, on-cell touch panels and in-cell touch panels. An add-on touch panel is obtained by separately producing a touch screen and a liquid crystal display (LCD) and then attaching the touch screen and the LCD together to form an LCD with touch function. Such an add-on touch panel has the defects of high production cost, low light transmittance, great module thickness and so on. An in-cell touch panel is obtained by embedding touch electrodes of a touch screen within an LCD, which not only can reduce the overall thickness of a module but also can greatly reduce the production costs of the touch screen, and is favored by major panel manufacturers.
Currently, an in-cell touch panel utilizes the principle of mutual capacitance or self-capacitance to achieve the function of detecting a finger touch position. In the self-capacitance principle, self-capacitance electrodes disposed on the same layer and insulated from each other may be arranged in the touch panel. When a human body does not touch the screen of the panel, the capacitance produced by the self-capacitance electrodes is at a fixed value. When a human body touches the screen of the panel, the capacitance produced by corresponding self-capacitance electrodes is the sum of the fixed value and the capacitance due to the human body. The touch detection chip can determine the touch position by detecting the capacitance value variation of the self-capacitance electrodes during a touch period (interval). As the capacitance of the human body can be imposed on the capacitance of all the self-capacitance electrodes, compared with the case that the capacitance of the human body can only be imposed on the projected capacitance of mutual capacitance electrodes, the capacitance variation amount caused by the touch of the human body on the touch panel will be larger than that of the touch panel manufactured in the principle of mutual capacitance. Therefore, compared with a mutual-capacitance touch panel, a self-capacitance touch panel can effectively improve the signal-to-noise (S/N) ratio of touch and hence improve the accuracy of touch sensing.